stats: Fix i18n not working in stats page.

Part of #16094.

Strings tagged with i18n were not being translated on the stats page.
This was because the translation data wasn't being sent to the front
end for this page.  That logic will be required in any page with a
bundle containing i18n JavaScript.

analytics/views.py

@@ -18,6 +18,7 @@ from django.http import HttpRequest, HttpResponse, HttpResponseNotFound
 from django.shortcuts import render
 from django.template import loader
 from django.urls import reverse
+from django.utils import translation
 from django.utils.timesince import timesince
 from django.utils.timezone import now as timezone_now
 from django.utils.translation import ugettext as _
@@ -51,6 +52,7 @@ from zerver.lib.actions import (
     do_send_realm_reactivation_email,
 )
 from zerver.lib.exceptions import JsonableError
+from zerver.lib.i18n import get_language_translation_data
 from zerver.lib.realm_icon import realm_icon_url
 from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_error, json_success
@@ -98,6 +100,14 @@ def render_stats(request: HttpRequest, data_url_suffix: str, target_name: str,
         remote=remote,
         debug_mode=False,
     )
+
+    request_language = translation.get_language_from_path(request.path_info)
+    if request_language is None:
+        request_language = request.user.default_language
+    translation.activate(request_language)
+
+    page_params["translation_data"] = get_language_translation_data(request_language)
+
     return render(request,
                   'analytics/stats.html',
                   context=dict(target_name=target_name,